an8022l Panasonic Corporation of North America, an8022l Datasheet - Page 7

• Manufacturer Part Number: an8022l
• Description: Ac-dc Switching Power Supply Control Ic
• Manufacturer: Panasonic Corporation of North America

Voltage Regulators
[1] Main characteristics [Load: C
[2] Operation descriptions
1. Start/stop circuit block
Application Notes (continued)
Note) To start up the IC operation, the startup current which is a pre-start current plus a circuit drive current is necessary.
4.5
4.0
3.5
3.0
2.5
OVP operating bias current characteristics 1
Start mechanism
voltage reaches the start voltage through the cur-
rent from the start resistor, the IC starts opera-
tion. Then the power MOSFET driving starts.
Thereby, bias is generated in the transformer
and the supply voltage is given from the bias
coil to the IC. (This is point a in figure 1.)
start voltage is reached and the voltage is gen-
erated in the bias coil to the time when the IC is
provided with a sufficient supply voltage, the
supply voltage of the IC is supplied by the ca-
pacitor (C1) connected to V
creases during the above period (area b in figure
1), the power supply is not able to start (state c
in figure 1), if the stop voltage of the IC is
reached before the sufficient supply voltage is
supplied from the bias coil.
Function
of IC when V
voltage (9.2 V typical). A large voltage difference is set between start and stop (5.0 V typical), so that it is easier
to select the start resistor and the capacitor to be connected to V
-50
When AC voltage is applied and the supply
During the period from the time when the
Since the supply voltage continuously de-
The start/stop circuit block is provided with the function to monitor the V
Set the resistance value so as to supply a startup current of 450 A.
-25
Ambient temperature ( C)
CC
0
voltage reaches the start voltage (14.2 V typical), and to stop when it decreases under the stop
25
50
CC
V
.
L
CC
75
3 300 pF, R
20 V
100
L
Start voltage
Stop voltage
20
] (continued)
2.5
2.0
1.5
1.0
0.5
OVP operating bias current characteristics 2
-50
After AC rectification
CC
Before start
.
GND
Start resistance
-25
V
V
OUT
Ambient temperature ( C)
CC
0
CC
voltage, and to start the operation
AN8022L, AN8022SB
R1
Figure 1
25
C1
a
b
50
V
Start
CC
c
Voltage supplied
from bias coil
75
Start condition
Start failure
10 V
100
7